This invention relates to a new and improved switch operating mechanism particularly intended for use with loadbreak pressure contact switches, adapted for manual operation from a side of the switch enclosure and having an optional enclosure door safety interlock.
Fused load break pressure contact switches are frequently used as service entrance equipment and in other relatively high current applications. Typically, switches of this type may be used in multipole switching applications requiring interruption under load of currents of the order of 400 to 6,000 amperes. In such switches, it is critically important that the contacts open and close rapidly to minimize arcing and thereby avoid pitting and deterioration of the contact members. Most switches of this kind are provided with a latching mechanism for each pole of the switch to secure the contacts in closed position and prevent any accidental opening of the switch due to external shocks or other factors. The switch blades are relatively heavy and mechanical forces involved in opening and closing of the switch may be substantial.
Rapid opening and closing of the switch contacts is accomplished by overcenter toggle spring mechanisms which accelerate the speed of opening and closing of the switch contacts. Spring mechanisms of this type have used lost motion mechanisms operatively connected between the operator's handle and the switch contacts. Mechanisms of this type provide manual opening of the switch contacts to a point at which disengagement is almost achieved, followed by a rapid spring actuated movement of the switch blades clear of the fixed switch contacts.
Many previously known switch operating mechanisms of this general type have been designed for operation from the front of the switch enclosure. Further, interlock mechanisms to prevent opening of the switch enclosure when the switch contacts are closed and closing of the switch contacts when the enclosure access door is open have been complicated and expensive.